package com.may._6;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

class ShareData{//资源类
    private int number = 0;
    private Lock lock = new ReentrantLock();
    private Condition condition = lock.newCondition();

    public void increment() throws Exception{
        lock.lock();
       try {
           while (number != 0){
               condition.await();
           }
           number++;
           System.out.println(Thread.currentThread().getName()+"\t "+number);
           condition.signalAll();
       }catch (Exception e){
           e.printStackTrace();
       }finally {
           lock.unlock();
       }
    }

    public void decrement() throws Exception{
        lock.lock();
        try {
            while (number == 0){
                condition.await();
            }
            number--;
            System.out.println(Thread.currentThread().getName()+"\t "+number);
            condition.signalAll();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }
}

/**
 * 一个初始值为 0 的便变量，两个线程对其交替操作，一个加 1，一个减 1。
 */
public class ProdConsumer_TraditionDemo {
    public static void main(String[] args) {

        ShareData shareData = new ShareData();
        new Thread(() -> {
            for (int i = 0; i < 5; i++) {
                try {
                    shareData.increment();
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
         },"A").start();

        new Thread(() -> {
            for (int i = 0; i < 5; i++) {
                try {
                    shareData.decrement();
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
        },"B").start();
    }
}
